The temperature, the load current and the saturation voltage (on-state voltage) of a power semiconductor component, for example an IGBT or MOS-FET, are important operating quantities, a knowledge of which is advantageous for a disturbance-free and dependable operation of an electrical circuit with power semiconductor components in order to be able to recognize overload conditions in time and, potentially, to initiate suitable counter-measures for protecting the component and connected users.
IGBTs having integrated sensors for acquiring the load current are known, for example, from the article by Bodo Arlt having the title "IGBT-Technik vom Erfinder" in the periodical Elektronik Industrie 1-1992, pages 14-18. A test current is thereby generated with the assistance of a current mirror, this test current being converted with the assistance of an external resistor into a test voltage proportional to the load current.
However, a temperature increase given, for example, a constant load current leads to an increase in the test voltage and thus simulates an increased load current. The measuring error arising particularly occurs when the precision resistor is integrated within the active area of the power semiconductor and is heated in common with the component as a result of the load current.